Size It Up is a free online daily size guessing game. Each round presents two objects on a blueprint grid. One object, called the yardstick, is drawn at true scale with its real measurement displayed beside it and remains fixed during play. The other object appears as a dashed white outline that the player grows or shrinks until it appears correctly sized relative to the yardstick. Pressing Measure reveals the real outline in yellow and displays the player's accuracy, stars earned, and the size expressed in familiar terms, such as about three school buses long. The game offers five new rounds daily, with a maximum of fifteen stars per daily set. The game uses 150 hand-drawn objects, including animals, landmarks, vehicles, planets, trees, instruments, and everyday items, with sizes ranging from a garden ant to the Sun. It is based on the observation that people often misjudge the size of objects they have only seen in photographs, where distance, shadows, and nearby references are absent. Because the yardstick is always drawn at true scale, each round provides a fair comparison. Scoring is calculated by dividing the smaller of the guessed size and the real size by the larger, yielding an accuracy percentage. The game also provides tips such as using known anchors like an adult's height or a school bus length, reading the yardstick first, noting whether an object is measured by height, length, or diameter, and using the grid labels. Typical use involves adjusting the dashed outline by dragging across the board, pinching, using a slider, or pressing arrow keys, then pressing Measure to compare the guess with reality. Size It Up requires JavaScript to be enabled. In addition to the daily puzzle, the site offers past puzzles and an unlimited play mode. Players can use the daily sets to practice and observe changes in their accuracy over time, as the yellow reveal shows both the direction and magnitude of any error.